1. Field of the Invention
The present invention relates to a technology for controlling a power automatically, and more particularly, to a smart server and smart device. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for controlling a power based on electricity charges.
2. Discussion of the Related Art
Generally, such an electric appliance as a home appliance used at home, a business machine used at office and the like is supplied with power via a transmission line from a power plant. Meanwhile, regarding an externally supplied electricity, a power unit price, which is the charge per unit power (energy), may vary per time slot. Hence, electric charges per month (or per unit period) are calculated in a manner of applying the power unit price to a power consumption quantity per time slot.
In case that such an independent power generator as a solar power generator, a wind power generator and the like is installed at home, the internally generated electricity is preferentially used rather than the externally supplied electricity. Thus, in case that the internal electricity sufficient for a total power demand of home appliances is generated by the independent power generator, the demand for the externally supplied electricity is reduced or becomes zero.
When a power saving function is performed according to a power unit price for an externally supplied electricity (i.e., charges per unit power), a power saving mode or an ultra-power saving mode can be automatically entered in a time slot having a high external power unit price. If this function is performed, when the external electricity is not necessary due to the sufficient internally generated electricity, the power saving mode is in appropriately entered due to the high external power unit price even if actual electric charges of the external electricity are very small despite the high external power unit price.